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@@ -97,7 +97,8 @@ struct fscache_operation {
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#define FSCACHE_OP_WAITING 4 /* cleared when op is woken */
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#define FSCACHE_OP_EXCLUSIVE 5 /* exclusive op, other ops must wait */
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#define FSCACHE_OP_DEC_READ_CNT 6 /* decrement object->n_reads on destruction */
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-#define FSCACHE_OP_KEEP_FLAGS 0x0070 /* flags to keep when repurposing an op */
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+#define FSCACHE_OP_UNUSE_COOKIE 7 /* call fscache_unuse_cookie() on completion */
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+#define FSCACHE_OP_KEEP_FLAGS 0x00f0 /* flags to keep when repurposing an op */
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enum fscache_operation_state state;
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atomic_t usage;
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@@ -150,7 +151,7 @@ struct fscache_retrieval {
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void *context; /* netfs read context (pinned) */
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struct list_head to_do; /* list of things to be done by the backend */
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unsigned long start_time; /* time at which retrieval started */
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- unsigned n_pages; /* number of pages to be retrieved */
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+ atomic_t n_pages; /* number of pages to be retrieved */
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};
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typedef int (*fscache_page_retrieval_func_t)(struct fscache_retrieval *op,
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@@ -194,15 +195,14 @@ static inline void fscache_enqueue_retrieval(struct fscache_retrieval *op)
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static inline void fscache_retrieval_complete(struct fscache_retrieval *op,
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int n_pages)
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{
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- op->n_pages -= n_pages;
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- if (op->n_pages <= 0)
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+ atomic_sub(n_pages, &op->n_pages);
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+ if (atomic_read(&op->n_pages) <= 0)
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fscache_op_complete(&op->op, true);
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}
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/**
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* fscache_put_retrieval - Drop a reference to a retrieval operation
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* @op: The retrieval operation affected
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- * @n_pages: The number of pages to account for
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*
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* Drop a reference to a retrieval operation.
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*/
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@@ -314,6 +314,7 @@ struct fscache_cache_ops {
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struct fscache_cookie {
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atomic_t usage; /* number of users of this cookie */
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atomic_t n_children; /* number of children of this cookie */
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+ atomic_t n_active; /* number of active users of netfs ptrs */
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spinlock_t lock;
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spinlock_t stores_lock; /* lock on page store tree */
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struct hlist_head backing_objects; /* object(s) backing this file/index */
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@@ -326,13 +327,11 @@ struct fscache_cookie {
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unsigned long flags;
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#define FSCACHE_COOKIE_LOOKING_UP 0 /* T if non-index cookie being looked up still */
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-#define FSCACHE_COOKIE_CREATING 1 /* T if non-index object being created still */
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-#define FSCACHE_COOKIE_NO_DATA_YET 2 /* T if new object with no cached data yet */
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-#define FSCACHE_COOKIE_PENDING_FILL 3 /* T if pending initial fill on object */
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-#define FSCACHE_COOKIE_FILLING 4 /* T if filling object incrementally */
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-#define FSCACHE_COOKIE_UNAVAILABLE 5 /* T if cookie is unavailable (error, etc) */
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-#define FSCACHE_COOKIE_WAITING_ON_READS 6 /* T if cookie is waiting on reads */
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-#define FSCACHE_COOKIE_INVALIDATING 7 /* T if cookie is being invalidated */
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+#define FSCACHE_COOKIE_NO_DATA_YET 1 /* T if new object with no cached data yet */
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+#define FSCACHE_COOKIE_UNAVAILABLE 2 /* T if cookie is unavailable (error, etc) */
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+#define FSCACHE_COOKIE_INVALIDATING 3 /* T if cookie is being invalidated */
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+#define FSCACHE_COOKIE_RELINQUISHED 4 /* T if cookie has been relinquished */
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+#define FSCACHE_COOKIE_RETIRED 5 /* T if cookie was retired */
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};
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extern struct fscache_cookie fscache_fsdef_index;
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@@ -341,45 +340,40 @@ extern struct fscache_cookie fscache_fsdef_index;
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* Event list for fscache_object::{event_mask,events}
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*/
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enum {
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- FSCACHE_OBJECT_EV_REQUEUE, /* T if object should be requeued */
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+ FSCACHE_OBJECT_EV_NEW_CHILD, /* T if object has a new child */
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+ FSCACHE_OBJECT_EV_PARENT_READY, /* T if object's parent is ready */
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FSCACHE_OBJECT_EV_UPDATE, /* T if object should be updated */
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FSCACHE_OBJECT_EV_INVALIDATE, /* T if cache requested object invalidation */
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FSCACHE_OBJECT_EV_CLEARED, /* T if accessors all gone */
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FSCACHE_OBJECT_EV_ERROR, /* T if fatal error occurred during processing */
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- FSCACHE_OBJECT_EV_RELEASE, /* T if netfs requested object release */
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- FSCACHE_OBJECT_EV_RETIRE, /* T if netfs requested object retirement */
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- FSCACHE_OBJECT_EV_WITHDRAW, /* T if cache requested object withdrawal */
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+ FSCACHE_OBJECT_EV_KILL, /* T if netfs relinquished or cache withdrew object */
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NR_FSCACHE_OBJECT_EVENTS
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};
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#define FSCACHE_OBJECT_EVENTS_MASK ((1UL << NR_FSCACHE_OBJECT_EVENTS) - 1)
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+/*
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+ * States for object state machine.
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+ */
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+struct fscache_transition {
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+ unsigned long events;
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+ const struct fscache_state *transit_to;
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+};
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+
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+struct fscache_state {
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+ char name[24];
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+ char short_name[8];
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+ const struct fscache_state *(*work)(struct fscache_object *object,
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+ int event);
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+ const struct fscache_transition transitions[];
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+};
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+
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/*
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* on-disk cache file or index handle
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*/
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struct fscache_object {
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- enum fscache_object_state {
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- FSCACHE_OBJECT_INIT, /* object in initial unbound state */
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- FSCACHE_OBJECT_LOOKING_UP, /* looking up object */
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- FSCACHE_OBJECT_CREATING, /* creating object */
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-
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- /* active states */
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- FSCACHE_OBJECT_AVAILABLE, /* cleaning up object after creation */
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- FSCACHE_OBJECT_ACTIVE, /* object is usable */
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- FSCACHE_OBJECT_INVALIDATING, /* object is invalidating */
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- FSCACHE_OBJECT_UPDATING, /* object is updating */
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-
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- /* terminal states */
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- FSCACHE_OBJECT_DYING, /* object waiting for accessors to finish */
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- FSCACHE_OBJECT_LC_DYING, /* object cleaning up after lookup/create */
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- FSCACHE_OBJECT_ABORT_INIT, /* abort the init state */
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- FSCACHE_OBJECT_RELEASING, /* releasing object */
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- FSCACHE_OBJECT_RECYCLING, /* retiring object */
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- FSCACHE_OBJECT_WITHDRAWING, /* withdrawing object */
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- FSCACHE_OBJECT_DEAD, /* object is now dead */
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- FSCACHE_OBJECT__NSTATES
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- } state;
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-
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+ const struct fscache_state *state; /* Object state machine state */
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+ const struct fscache_transition *oob_table; /* OOB state transition table */
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int debug_id; /* debugging ID */
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int n_children; /* number of child objects */
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int n_ops; /* number of extant ops on object */
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@@ -390,6 +384,7 @@ struct fscache_object {
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spinlock_t lock; /* state and operations lock */
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unsigned long lookup_jif; /* time at which lookup started */
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+ unsigned long oob_event_mask; /* OOB events this object is interested in */
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unsigned long event_mask; /* events this object is interested in */
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unsigned long events; /* events to be processed by this object
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* (order is important - using fls) */
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@@ -398,6 +393,9 @@ struct fscache_object {
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#define FSCACHE_OBJECT_LOCK 0 /* T if object is busy being processed */
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#define FSCACHE_OBJECT_PENDING_WRITE 1 /* T if object has pending write */
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#define FSCACHE_OBJECT_WAITING 2 /* T if object is waiting on its parent */
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+#define FSCACHE_OBJECT_IS_LIVE 3 /* T if object is not withdrawn or relinquished */
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+#define FSCACHE_OBJECT_IS_LOOKED_UP 4 /* T if object has been looked up */
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+#define FSCACHE_OBJECT_IS_AVAILABLE 5 /* T if object has become active */
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struct list_head cache_link; /* link in cache->object_list */
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struct hlist_node cookie_link; /* link in cookie->backing_objects */
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@@ -415,62 +413,40 @@ struct fscache_object {
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loff_t store_limit_l; /* current storage limit */
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};
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-extern const char *fscache_object_states[];
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+extern void fscache_object_init(struct fscache_object *, struct fscache_cookie *,
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+ struct fscache_cache *);
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+extern void fscache_object_destroy(struct fscache_object *);
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-#define fscache_object_is_active(obj) \
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- (!test_bit(FSCACHE_IOERROR, &(obj)->cache->flags) && \
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- (obj)->state >= FSCACHE_OBJECT_AVAILABLE && \
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- (obj)->state < FSCACHE_OBJECT_DYING)
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+extern void fscache_object_lookup_negative(struct fscache_object *object);
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+extern void fscache_obtained_object(struct fscache_object *object);
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-#define fscache_object_is_dead(obj) \
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- (test_bit(FSCACHE_IOERROR, &(obj)->cache->flags) && \
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- (obj)->state >= FSCACHE_OBJECT_DYING)
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+static inline bool fscache_object_is_live(struct fscache_object *object)
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+{
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+ return test_bit(FSCACHE_OBJECT_IS_LIVE, &object->flags);
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+}
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-extern void fscache_object_work_func(struct work_struct *work);
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+static inline bool fscache_object_is_dying(struct fscache_object *object)
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+{
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+ return !fscache_object_is_live(object);
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+}
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-/**
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- * fscache_object_init - Initialise a cache object description
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- * @object: Object description
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- *
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- * Initialise a cache object description to its basic values.
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- *
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- * See Documentation/filesystems/caching/backend-api.txt for a complete
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- * description.
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- */
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-static inline
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-void fscache_object_init(struct fscache_object *object,
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- struct fscache_cookie *cookie,
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- struct fscache_cache *cache)
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+static inline bool fscache_object_is_available(struct fscache_object *object)
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{
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- atomic_inc(&cache->object_count);
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-
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- object->state = FSCACHE_OBJECT_INIT;
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- spin_lock_init(&object->lock);
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- INIT_LIST_HEAD(&object->cache_link);
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- INIT_HLIST_NODE(&object->cookie_link);
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- INIT_WORK(&object->work, fscache_object_work_func);
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- INIT_LIST_HEAD(&object->dependents);
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- INIT_LIST_HEAD(&object->dep_link);
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- INIT_LIST_HEAD(&object->pending_ops);
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- object->n_children = 0;
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- object->n_ops = object->n_in_progress = object->n_exclusive = 0;
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- object->events = object->event_mask = 0;
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- object->flags = 0;
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- object->store_limit = 0;
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- object->store_limit_l = 0;
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- object->cache = cache;
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- object->cookie = cookie;
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- object->parent = NULL;
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+ return test_bit(FSCACHE_OBJECT_IS_AVAILABLE, &object->flags);
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}
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-extern void fscache_object_lookup_negative(struct fscache_object *object);
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-extern void fscache_obtained_object(struct fscache_object *object);
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+static inline bool fscache_object_is_active(struct fscache_object *object)
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+{
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+ return fscache_object_is_available(object) &&
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+ fscache_object_is_live(object) &&
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+ !test_bit(FSCACHE_IOERROR, &object->cache->flags);
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+}
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-#ifdef CONFIG_FSCACHE_OBJECT_LIST
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-extern void fscache_object_destroy(struct fscache_object *object);
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-#else
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-#define fscache_object_destroy(object) do {} while(0)
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-#endif
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+static inline bool fscache_object_is_dead(struct fscache_object *object)
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+{
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+ return fscache_object_is_dying(object) &&
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+ test_bit(FSCACHE_IOERROR, &object->cache->flags);
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+}
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/**
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* fscache_object_destroyed - Note destruction of an object in a cache
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@@ -531,6 +507,33 @@ static inline void fscache_end_io(struct fscache_retrieval *op,
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op->end_io_func(page, op->context, error);
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}
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+/**
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+ * fscache_use_cookie - Request usage of cookie attached to an object
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+ * @object: Object description
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+ *
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+ * Request usage of the cookie attached to an object. NULL is returned if the
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+ * relinquishment had reduced the cookie usage count to 0.
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+ */
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+static inline bool fscache_use_cookie(struct fscache_object *object)
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+{
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+ struct fscache_cookie *cookie = object->cookie;
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+ return atomic_inc_not_zero(&cookie->n_active) != 0;
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+}
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+
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+/**
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+ * fscache_unuse_cookie - Cease usage of cookie attached to an object
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+ * @object: Object description
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+ *
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+ * Cease usage of the cookie attached to an object. When the users count
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+ * reaches zero then the cookie relinquishment will be permitted to proceed.
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+ */
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+static inline void fscache_unuse_cookie(struct fscache_object *object)
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+{
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+ struct fscache_cookie *cookie = object->cookie;
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+ if (atomic_dec_and_test(&cookie->n_active))
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+ wake_up_atomic_t(&cookie->n_active);
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+}
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+
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/*
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* out-of-line cache backend functions
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*/
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Linus Torvalds